The present invention relates to wide area cordless telephone systems, and more specifically to registration and cancellation control in a wide area cordless telephone system.
In the wide area cordless telephone system, the whole service area of the system is divided into a plurality of local service areas. In each local area, radio access units are located at several key points to establish radio links between cordless telephones and a public switched network directly or via a private branch exchange (PBX). Cordless telephones are permanently assigned unique telephone numbers of the PBX or public switched network if they remain within the boundary of their home position local area and temporarily assigned a different number whenever they roam into another local area. Assignment of the temporary telephone number requires that the system be provided with information on the current location of each cordless telephone. Each of the cordless telephones of the system must therefore be registered exclusively in one of the local areas. Whenever it moves to another local area, however, the registration must be cancelled in the source area in favor of a new registration in the destination area.
Japan Telecommunications Review, January 1979, pages 44-50 (High Capacity Automobile Telephone System) describes a method for making registration of mobile subscriber stations. According to this method, the mobile subscriber station transmits a registration request signal on crossing a boundary between two service areas, the signal being received by a mobile control station and relayed to an automobile switching center. The switching center keeps a record of each mobile subscriber station located within the own area.